---

添付ファイル5.1

アメリカン大通り一零九五号 ニューヨークニューヨーク郵便番号：10036-6797 +1-212-698-3500 +1-212-698-3599ファックス www.dechert.com

2024年4月3日

女性たち、さんたち：

私たちは米国デラウェア州会社(以下、“当社”と略す)のAqutive Treeutics，Inc.の法律顧問を務め、本日改正された1933年証券法(“証券法”)に基づいて米国証券取引委員会(“委員会”)に提出されたS-3表を採用した登録声明(“登録声明”)に関連し、当社が提案する公開発行株に関連し、総金額は最高$250，000，000，000当社の以下の証券：(1)普通株、会社は1株当たり0.001ドルです(“普通株”)。(2)会社の優先株、1株当たり額面0.001ドルの株式(“優先株”)、(3)会社が普通株、優先株、債務証券または単位の引受権証(“株式承認証”)(“株式承認証”)、(4)br}会社とその中で指定された受託者(“受託者”)との間の契約によって発行された債務証券(“受託者”)を購入する(この契約は時々改訂または補充することができ、“契約”と呼ぶ)。(5)会社が普通株、優先株、債務証券又は単位を購入する権利(“権利”)；及び(6)普通株、優先株、株式承認証、債務証券又は権利(“単位”)の任意の組み合わせからなる会社単位。普通株、優先株、株式承認証、債務証券、権利と単位は本明細書で総称して証券と呼ばれる

登録説明書は、当該等の証券は、募集説明書(登録説明書及び登録説明書の一部に記載されている)に記載されている入札説明書に記載されている金額、価格及び条項、又は登録説明書に記載されている募集説明書の1部又は複数部の副刊(1部当たり“目論見説明書副刊”)内でそれぞれ発売又は一括して発売することができると規定している。

本意見書は、証券法S-K条例第601(B)(5)項の要求に基づいて当社に提出されたものであり、本意見書は、登録声明内容に関する事項については何も意見を述べていないが、以下に述べる証券の有効性は除く。

Aqutive Treeutics，Inc.
2024年4月3日
2ページ

本意見が根拠としている事実については，吾らは適切と考えられる範囲で公職者の証明書や当社の代理人，上級者，役員，従業員および代表および会計士の書面声明に依存しており，この点でこのような証明書や声明の真正性を仮定している。私たちはこのような依存的な事実を独立的に確立していない。

我々の審査では，すべての署名の真正性，我々に提出されたすべての文書のオリジナル文書としての真正性，コピーとして我々に提出されたすべての文書と元の文書との整合性 ，我々が検査した文書である署名者である自然人の法的行動能力，およびすべての文書当事者(会社を除く)の署名を代表するすべての人の法的権力と権威を仮定する.我々 はさらに，以下の意見ベースを構成するための任意のプロトコル，文書，または文書に口頭修正，修正または補足(明示的または暗黙的な棄却を含む) がないと仮定する.

以上のことから，本手紙で述べた仮定，制限，制約を満たすことを前提として，本手紙の日付までは以下のように考えられる

Aqutive Treeutics，Inc.
2024年4月3日
3ページ

The opinions set forth herein are subject to the following assumptions, qualifications, limitations and exceptions being true and correct at or before the time of the delivery of any Securities offered pursuant to the Registration Statement and appropriate Prospectus Supplement: (i) the Board of Directors, including any appropriate committee appointed thereby, shall have (x) duly established the terms of the Securities (and in the case of the Units, the Securities that are the components thereof), and (y) duly authorized and taken any other necessary corporate or other action to approve the creation, if applicable, issuance and sale of the Securities and related matters (including with respect to Preferred Stock, the execution, acknowledgment and filing of a Certificate of Designation stating the designation and voting rights, preferences, limitations and special rights, if any, of any such Preferred Stock in accordance with the applicable provisions of the General Corporation Law of the State of Delaware) and any Securities consisting of Common Stock or Preferred Stock, and any Common Stock or Preferred Stock for or into which any other Securities are exercisable, exchangeable or convertible, shall have been duly reserved for issuance and such authorizations and actions have not been rescinded; (ii) the resolutions establishing the definitive terms of and authorizing the Company to register, offer, sell and issue the Securities shall remain in effect and unchanged at all times during which the Securities are offered, sold or issued by the Company; (iii) the definitive terms of each class and series of the Securities not presently provided for in the Registration Statement or the certificate of incorporation of the Company, and the terms of the issuance and sale of the Securities (x) shall have been duly established in accordance with all applicable law and the Charter, the Indenture (including any amendments or supplements thereto), underwriting agreement, warrant agreement, subscription agreement, unit agreement and any other relevant agreement relating to the terms and the offer and sale of the Securities (collectively, the “Documents”) and the authorizing resolutions of the Board of Directors, and reflected in appropriate documentation reviewed by us, and (y) shall not violate any applicable law, the Charter or the Documents (subject to the further assumption that such Charter and Documents have not been amended from the date hereof in a manner that would affect the validity of any of the opinions rendered herein), or result in a default under or breach of any agreement or instrument binding upon the Company and so as to comply with any restriction imposed by any court or governmental body having jurisdiction over the Company; (iv) upon issuance of any shares of Preferred Stock or Common Stock, or, in the case of Units, of which shares of Preferred Stock or Common Stock are components, including upon exercise, conversion or exchange of Securities, the total number of shares of Preferred Stock or Common Stock issued and outstanding shall not exceed the total number of shares of Preferred Stock or Common Stock that the Company is then authorized to issue under its certificate of incorporation; (v) the interest rate on the Debt Securities shall not be higher than the maximum lawful rate permitted from time to time under applicable law; (vi) the Securities (including any Securities issuable upon exercise, conversion or exchange of other Securities and, in the case of any Units, the Securities that are components thereof), and any certificates or instruments representing the relevant Securities (including any Securities issuable upon exercise, conversion or exchange of other Securities and, in the case of any Units, the Securities that are components thereof), have been duly authenticated, executed, countersigned, registered and delivered upon payment of the agreed-upon legal consideration therefor and have been duly issued and sold in accordance with any relevant agreement, approved by us and, if applicable, duly executed and delivered by the Company and any other appropriate party; (vii) the Indenture (including any amendments or supplements thereto), warrant agreement, subscription agreement, unit agreement and any other relevant agreement has been duly authorized, executed and delivered by, and will constitute a valid and binding obligation of, each party thereto (other than the Company); (viii) the Registration Statement, as amended (including all necessary post-effective amendments), and any additional registration statement filed under Rule 462, shall be effective under the Securities Act, and such effectiveness shall not have been terminated or rescinded; (ix) an appropriate Prospectus Supplement shall have been prepared, delivered and filed in compliance with the Securities Act and the applicable rules and regulations thereunder describing the Securities offered thereby; (x) the Securities shall be issued and sold in compliance with all federal and state securities laws and solely in the manner stated in the Registration Statement and the applicable Prospectus Supplement and there shall not have occurred any change in law affecting the validity of the opinions rendered herein; (xi) if the Securities will be sold pursuant to a firm commitment underwritten offering, the underwriting agreement with respect to the Securities in the form filed as an exhibit to the Registration Statement or any post-effective amendment thereto, or incorporated by reference therein, has been duly authorized, executed and delivered by the Company and the other parties thereto; (xii) the Indenture (including any amendments or supplements thereto) shall have been duly qualified under the Trust Indenture Act of 1939, as amended; (xiii) each agreement or contract referred to herein but not filed as an exhibit to the Registration Statement as of the date hereof shall be governed by the laws of the State of New York; and (xiv) in the case of an agreement or instrument pursuant to which any Securities are to be issued, there shall be no terms or provisions contained therein which would affect the validity of any of the opinions rendered herein.

Aquestive Therapeutics, Inc.
April 3, 2024
Page 4

Any opinion set forth herein as to enforceability of obligations of the Company is subject to: (i) bankruptcy, insolvency, reorganization, fraudulent conveyance, moratorium or similar laws now or hereinafter in effect affecting the enforcement of creditors’ rights generally, and by general principles of equity (regardless of whether enforcement is sought in a proceeding in equity or at law) and the discretion of the court or other body before which any proceeding may be brought; (ii) provisions of law that may require that a judgment for money damages rendered by a court in the United States be expressed only in United States dollars; (iii) requirements that a claim with respect to any Debt Securities denominated other than in U.S. dollars (or a judgment denominated other than in U.S. dollars in respect of such claim) be converted into U.S. dollars at a rate of exchange prevailing on a date determined pursuant to applicable law; and (iv) governmental authority to limit, delay or prohibit the making of payments outside the United States or in foreign currency or composite currency.

We express no opinion as to the validity, legally binding effect or enforceability of any provision in any agreement or instrument that (i) requires or relates to payment of any interest at a rate or in an amount that a court would determine in the circumstances under applicable law to be higher than the maximum lawful rate permitted from time to time or (ii) relates to governing law and submission by the parties to the jurisdiction of one or more particular courts.

The opinion expressed herein is limited to the General Corporation Law of the State of Delaware. We are members of the bar of the State of New York. We express no opinion concerning the laws of any other jurisdiction, and we express no opinion concerning any state securities or “blue sky” laws, rules or regulations, or any federal, state, local or foreign laws, rules or regulations relating to the offer and/or sale of the Securities. The opinions expressed herein are based upon the law as in effect and the documentation and facts known to us on the date hereof.

This opinion letter has been prepared for your use solely in connection with the Registration Statement. We assume no obligation to advise you of any changes in the foregoing subsequent to the effectiveness of the Registration Statement.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the use of our name in the base prospectus contained therein, under the caption “Legal Matters.” In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act and the rules and regulations of the Commission thereunder.

---